@Richard_S_Wisner_Jr, these are Bluetooth headphones. Roon does not support playing to Bluetooth devices natively.
The only way to make them a “zone” with Roon is to make the headphones the default System Output device on the iMac, then play Roon to that iMac’s System Output (ensure it is “Enabled” in Roon’s Settings → Audio).
What @Robert_F states is perfectly correct and will work with any bluetooth headphones. However, those headphones deserve a better bluetooth driver. I use mine with the Sony Headphones app on my Android phone. This app installs and uses the Sony LDAC driver, which sounds wonderful with the WH1000-XM5. I use the Tidal app on the phone to supply music.
I don’t think you can install the LDAC driver on a Mac, but I may be wrong.
Indeed, but the good news is that use of the LDAC driver seems to be spreading. Worth looking out for when choosing new products if you use the better Sony headphones:
But LDAC is only really good in the home where there isn’t interference it’s very variable outside. I don’t use BT inside only wired. When I had Android and LDAC headset it rarely ever used the higher connection rates on my commutes as too much competition for airtime and dropped out regularly. I doubt this new APTX lossless will be lossless when out and about for same reasons. TBH find AAC on the iPhone is actually rather good overall for out and about use where fidelity is compromised anyway regardless of ANC or not.